Collimated packet of light rays diverging dramatically after a near-miss with a black hole
This program computes the trajectory of null geodesics around a Schwarzschild black hole, visualized by projecting off the time direction into a spacelike slice outside the event horizon. A tightly collimated packet of light rays is sent on a near-miss trajectory past the black hole, illustrating how neighboring geodesics diverge dramatically after passing close to the photon sphere at r=3M.
The menu at the upper right allows one to control the thickness of the original collection of geodesics, as well as their approach to the photon sphere. Controls: Click and drag to orbit, scroll to zoom.
